Future climate and demographic changes will almost double the risk of schistosomiasis transmission in the Lake...

The Lake Victoria Basin (LVB), supporting millions of people across Uganda, Kenya, Tanzania, Rwanda, and Burundi, is a critical freshwater ecosystem. However, it faces significant One Health challenges, notably urogenital and intestinal schistosomiasis, diseases transmitted by Bulinus and Biomphalaria snails, respectively. Climate, topography, environmental and demographic drivers influence snail habitat suitability and distribution, potentially increasing schistosomiasis risks for communities dependent on agriculture, fishing, and water-related livelihoods.

This study applied ecological ensemble modeling (Random Forest, XGBoost, and MaxEnt) to identify key drivers of habitat suitability, assessing current and future climate scenarios under Shared Socioeconomic Pathways, and overlaying habitat suitability and population density to quantify human exposure risks associated with Biomphalaria and Bulinus snails. Snail occurrence data were sourced from biodiversity databases, field surveys, and literature. Predictor variables included climatic (temperature, precipitation), topographic (elevation, slope, proximity to water bodies), and environmental (vegetation index, soil composition) features.

For Bulinus, habitat suitability increased with higher precipitation and elevation but decreased with rising vegetation index NDVI, silt content, and temperature seasonality as key drivers. Similarly, Biomphalaria suitability improved with higher precipitation and elevation but declined with increasing NDVI, slope, and temperature seasonality. Currently, Biomphalaria and Bulinus are primarily concentrated around Lake Victoria, with 17 % and 14 % of the area suitable for their habitat, a figure projected to increase to 21 % and 18 % by 2050. By 2050, medium -risk zones for intestinal schistosomiasis are expected to almost double from 13 % to 22 %, while those for urogenital schistosomiasis are projected to more than double from 8 % to 18 % of the total area. This study predicts a rising schistosomiasis risk across the LVB, emphasizing the need for targeted interventions. A proactive One Health approach, integrating environmental management, strategic disease control, and policy adaptation, is vital to reducing future risks and protecting vulnerable communities.